You Can Handle The Truth: What You Can Learn From Your Own DNA

Zachary Ende

Originally published March 2, 2015

photo by: jadiel wasson

Samuel L. Jackson is known for a plethora of apoplectic soliloquies, but you’ve probably never heard him say, "Wow, get out of here! I have to Google Gabon immediately, and see what’s there!" If you thought this was hyperbole-laden acting, you would be surprised to learn that he was reacting genuinely. All it took was the science of DNA. On the television show "Finding Your Roots," Samuel L. Jackson learned his DNA matched that of the Benga tribe of modern day Gabon, sparking his interest in the Central African nation.

The connection was made possible by Africanancestry.com, one of nearly a dozen personal genome sequencing companies that have sprouted up to decipher your DNA. Why now? DNA sequencing costs have plummeted precipitously as technology has rapidly evolved. Decoding an entire human genome went from over $100,000,000, in the year 2000, to $1,000,000 in 2007, to under $10,000 today. Most personal genome sequencing companies probe short informative regions of your DNA. These private companies can tell you amazing things about yourself. What kinds of things are hidden in our DNA?

All of humanity originated in East Africa roughly 150,000 years ago subsequently spreading throughout the world. For about $200, the National Genographic Project traces your ancestors' migration to the present day solely from skin cells on the inside of your mouth. They decode small portions of your skin cell derived DNA known to differ between people (single nucleotide polymorphisms or SNPs, pronounced "snips").

At most times during human evolution, more than one hominin species lived concurrently. Our habitually besmearched cousins, the Neanderthals, lived alongside modern humans up to about 30,000 years ago. In a landmark study published in 2010, Green et al. examined Neanderthal DNA in modern humans and showed that "non-African haplotypes match Neanderthal at an unexpected rate." Since then, other publications have suggested mixing probably occurred in the Middle East about 50,000 to 60,000 years ago. For non-Africans the average match to Neanderthal DNA is ~2%. You may find out you are part Neanderthal, literally.

I am admittedly a bit of a Neanderthal. How do I know? I tried 23andMe for $100. I also learned much more relevant information about my genetic predispositions. Some of the propensities they test for may surprise you: drug side effects (i.e. statins for cholesterol), diseases (i.e. various cancers, asthma and dementias) and, physical and metabolic traits (i.e. height, food preference, and aging).

These tests also surprised the Federal Drug Administration (FDA) of the United States government. The FDA told 23andMe to "immediately discontinue marketing" in an official warning letter on November 22, 2013, until approval is granted for the health risk assessments (though they still give you the raw data). Why would the government block us from potentially valuable health information found in our own DNA?  

The warning letter cited concerns "about the public health consequences of inaccurate results." The FDA categorized the DNA service as a medical device and thus expressed concern about false negatives, false positives, and misinterpretations by consumers that could lead to bad healthcare decisions.

Not everyone supports the FDA's decision. Robert Green is one formidable dissenter if there ever was one. He is an M.D., M.P.H. in the Division of Genetics at Harvard Medical School and is also part of "The Impact of Personal Genomics Study." In a comment in the journal Nature, Green and Nita Farahany, a law professor at the Duke Institute for Genome Sciences and Policy, said that "a US drug-agency clampdown is unwarranted without evidence of harm," and, " we urge the FDA to let consumer genomics testing proceed." Most people (~60%) do nothing when learning of their genetic risk factors, while over a quarter of people change exercising and eating habits for the better. Other articles in the Journal of the American Medical Association and the New England Journal of Medicine support the FDA's decision, though Green and Farahany's arguments are the most convincing since they have actually studied the issues in play.

Putting aside the argument about the paternalistic stance of the FDA, maybe this information is too heavy for many of us to consider knowing on an emotional level. After all, besides the disease risks, we could find unknown half siblings (search "With genetic testing, I gave my parents the gift of divorce" for an interesting story about an anonymous 23andMe customer who reported just that). On the other hand, knowledge is power, and perhaps you will discover important facts about your genetic risk factors for you and your children.

Of utmost concern is privacy and data security. The Genetic Information Nondiscrimination Act of 2008 protects those in the United States from discrimination based on genetic information in the realm of insurance and employment. That information alone is not enough to allay most people's fears. Most would-be consumers I have spoken with said privacy is paramount in their minds and the top reason for not participating in personal genome sequencing.

23andMe may as well be considered a side project of Google given that 23andMe CEO Anne Wojcicki is the wife of Google Co-Founder Sergey Brin (it is not just gossip, it is also a $3.9 million investment in 2007). Google's connection is unsettling on the one hand given the fear that our own DNA could end up being "Googled" or worse yet added to the ungodly amounts of data Google has on us.  On the other hand, Google is a technological mammoth that one would imagine has resources and know-how to protect private information—if anyone can.

I shared my 23andMe results with any of my family members that would listen—both ancestry and health-related analyses. My own experience was a journey of self-discovery and personal empowerment; friends who have tried the service have echoed that sentiment on the whole. Nevertheless, improved sequencing methods leading to lower costs and a better understanding of the results will enable a more complete DNA decoding experience than the "snips" currently offer. That is why, for those considering paying for DNA sequencing services, like those considering purchasing the newest computer or smart phone, you will likely be rewarded for your hesitation and indecision. As soon as you buy the new version, the newer improved version comes out a day later. But hey, like DNA, to each his own.